Method for manufacturing menthol

Preparing 2-isopropyl-5-methylcyclohexanol (D, L-menthol), comprises: (a) hydrogenating thymol with hydrogen in the presence of a catalyst and optionally in the presence of a solvent; (b) hydrogenating the 2-propyl-(2)-5-methylcyclohexanone (menthone) isolated from (a) with hydrogen in the presence of a catalyst as supported or unsupported catalysts, optionally in the presence of a solvent to give menthol; (c) separating neomenthol, which is formed alongside with menthol; and (d) optionally carrying out an isomerization reaction of neomenthol to give menthol. Preparing 2-isopropyl-5-methylcyclohexanol (D, L-menthol), comprises: (a) hydrogenating thymol with hydrogen in the presence of a catalyst consisting of elements of Group VIII B (iron-platinum-group) consisting of platinum, rhodium, ruthenium, and palladium, preferably palladium, and optionally in the presence of a solvent; (b) hydrogenating the 2-propyl-(2)-5-methylcyclohexanone (menthone) isolated from (a) with hydrogen in the presence of a catalyst from a group VIII b (iron-platinum group) consisting of platinum, rhodium, ruthenium and palladium, preferably rhodium as supported or unsupported catalysts, optionally in the presence of a solvent to give menthol; (c) separating neomenthol, which is formed alongside with menthol; and (d) optionally carrying out an isomerization reaction of neomenthol to give menthol, where the steps (a) and/or (c) are carried out at temperatures of 60-200[deg] C and at a pressure of 1.1 bar. Die Erfindung betrifft ein Verfahren zur Herstellung von 2-Isopropyl-5-methylcyclohexanol (D,L-Menthol) über die Hydrierung von Thymol zu Menthon und der anschließenden weiteren Hydrierung zum D,L-Menthol.